onsemi KSA1298PYWD

Overview

KSA1298PYWD from onsemi is a PNP epitaxial silicon transistor designed for low-frequency power amplifier applications, with −25 V V_CEO, −800 mA I_C, 200 mW P_C, and h_FE = 160–320 at I_C = −100 mA. It serves as a complementary device to the NPN KSC3265 in push-pull audio output stages and linear regulator pass elements.

For engineers reviewing the KSA1298PYWD datasheet, pinout, applications, or equivalent options, key selection criteria include its SOT-23 package compatibility, guaranteed h_FE grading, low V_CE(sat) of ≤−0.4 V at high current, and f_T of 120 MHz - critical for stable biasing and mid-band amplification in industrial control interfaces and DC-DC feedback loops.

Technical Context

This PNP bipolar junction transistor operates in active and saturation regions for linear amplification and switching, with base-emitter forward voltage (V_BE(on)) specified between −0.5 V and −0.8 V at I_C = −10 mA. Its f_T of 120 MHz supports bandwidth-limited low-frequency signal conditioning up to ~10 MHz.

The device features low leakage: I_CBO ≤ −100 nA at V_CB = −30 V and I_EBO ≤ −100 nA at V_BE = −5 V, enabling stable operation in temperature-sensitive analog circuits. Junction temperature rating of 150°C allows use in thermally constrained PCB layouts without derating below 200 mW at T_A = 25°C.

Key Specifications

Pinout & Package

SOT-23 (TO-236) surface-mount package, 2.90 mm × 1.30 mm × 1.00 mm body size, 1.90 mm lead pitch. Pb-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP low-frequency power amplifier applications.

Compared with MMBT4403 and KSA1281YTA, the KSA1298PYWD uniquely balances −800 mA current handling, −25 V rating, SOT-23 footprint, and guaranteed h_FE ≥ 160 - making it optimal for space-constrained, medium-power linear amplifier designs where thermal and matching performance are prioritized.

Availability

KSA1298PYWD is available at Aetrix Electronics and suitable for audio power amplifier stages, linear voltage regulator pass devices, industrial sensor signal conditioning, and DC-DC converter feedback amplifiers requiring stable component supply and consistent parametric performance across production batches.

Supply support for KSA1298PYWD includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The KSA1298PYWD belongs to onsemi's general-purpose bipolar transistor product line, engineered for reliable low-frequency amplification and switching in cost-sensitive, thermally constrained applications where SOT-23 packaging and matched complementary pairs are essential.

FAQ

What is the maximum collector current rating for KSA1298PYWD?

The KSA1298PYWD has an absolute maximum collector current (I_C) rating of −800 mA at T_A = 25°C. This value is defined under steady-state DC conditions and must be derated linearly above 25°C ambient per the device's thermal resistance specification. Operation at full −800 mA requires adequate PCB copper area and airflow to maintain junction temperature below 150°C. The KSA1298PYWD datasheet confirms this rating in the Absolute Maximum Ratings table.

Is KSA1298PYWD pin-compatible with KSC3265?

No, KSA1298PYWD is not pin-compatible with KSC3265 - they are complementary PNP/NPN devices with identical SOT-23 footprints but opposite pinouts. KSA1298PYWD uses Base–Emitter–Collector (pin 1–2–3), while KSC3265 uses Emitter–Base–Collector (pin 1–2–3). Layouts must assign separate footprints or use mirrored placement. The KSA1298PYWD datasheet explicitly states "complement to KSC3265" without claiming pin compatibility.

What is the typical current gain (h_FE) of KSA1298PYWD at low current?

The KSA1298PYWD exhibits h_FE = 160–320 at V_CE = −1 V and I_C = −100 mA, with minimum guaranteed value of 160. At lower currents (e.g., I_C = −10 mA), h_FE typically increases but is not characterized in the official datasheet. Designers should rely on the −100 mA test condition for guaranteed performance; the KSA1298PYWD datasheet does not specify h_FE min/max at I_C < −50 mA.

Does KSA1298PYWD support Pb-free soldering processes?

Yes, KSA1298PYWD is manufactured in a Pb-free (RoHS-compliant) SOT-23 package, qualified for standard reflow soldering profiles including JEDEC J-STD-020. The "Y" in the order code KSA1298YMTF denotes Pb-free construction, and the device meets IPC/JEDEC standard peak temperatures up to 260°C for 10 seconds. The KSA1298PYWD datasheet references BRD8011/D for tape-and-reel details and confirms Pb-free status in the Ordering Information section.

What is the safe operating area (SOA) limitation for KSA1298PYWD in switching applications?

The KSA1298PYWD does not publish a graphical SOA curve in its datasheet; safe operation in switching must be limited by simultaneous adherence to V_CEO ≤ −25 V, I_C ≤ −800 mA, P_C ≤ 200 mW, and second breakdown constraints implied by its f_T and C_ob. For pulsed switching, peak I_C must remain within −800 mA and pulse width must ensure average power stays below 200 mW. The KSA1298PYWD datasheet specifies only DC ratings - designers must perform thermal modeling for transient conditions.